The present invention relates to an image forming apparatus such as a laser printer.
As an image forming apparatus such a laser printer, an upright-type image forming apparatus is generally known. For example, Japanese Laid-open Patent Application No. 2003-302889 discloses such an upright-type image forming apparatus, in which a paper feed tray (recording sheet storage unit) for storing papers as recording sheets and a paper output tray (recording sheet receiving unit) are arranged back and forth with these trays positioned upright.
In this image forming apparatus, the paper feed tray is arranged higher than the paper output tray, so that a paper conveyance passage extending from a lower part of the paper feed tray to a lower part of the paper output tray for conveying a paper is bent to form an L-shaped configuration. An image forming unit which forms an image on a paper is positioned intermediate of this paper conveyance passage at an extension extending downward from the lower part of the paper feed tray.
More specifically, the image forming unit includes a developer unit equipped with a toner cartridge and a developing roller, and a fixing device for thermally fixing developer that is transferred on a paper. The image forming unit is arranged such that the fixing device is positioned below the developer unit on the paper conveyance passage. Further, in this image forming apparatus, the toner cartridge is arranged between the paper output tray and the paper feed tray.
However, in this image forming apparatus, because the fixing device is positioned below the developer unit, heat generated at the fixing device rises to the developer unit. This may cause the developer unit to be heated disadvantageously, and as a result heat deterioration of the developer may occur. Further, because this image forming apparatus is configured such that the toner cartridge is arranged between the paper output tray and the paper feed tray, the size of the whole apparatus becomes disadvantageously large in a horizontal direction.
In view of the foregoing drawbacks of the prior art, the present invention seeks to provide an upright-type image forming apparatus which can restrict an increase in the size of the apparatus in the horizontal direction as well as heat deterioration of the developer.